Science Physics MCQ-89

Consider the physical quantities1. Displacement2. Torque3. Current density4. Linear momentumWhich of the above are vector quantities?

3, 4 and 2

1,4 and 3

1, 2 and 3

1, 2, 3 and 4

Which of the following is not the unit of time?

Micro second

Parallactic second

Leap year

Solar day

Consider the following statements1 . Distance of stars is measured in light year . 2 . One astronomical unit (AU) is equal to 1 .495 x1011m . 3 . One parallax second (parsec) is equalto3 .08×1016m . Which of the statement(s) given above is/are correct?

Only 1

1 and 2

Only 2

1, 2 and 3

Consider the following statements1 . All plane angles are measured in radian . 2 . All the solid angles are measured in steradian . /3 . Solid angle is measured in steradian . Which of the statement(s) given above is/are correct?

Only 1

Only 3

2 and 3

1, 2 and 3

Which of the following physical quantities have the same dimensions?

Angular momentum and work

Kinetic energy and velocity

Work and torque

Potential energy and linear momentum

Unit of resistance is

volt x ampere

volt2 x ampere

volt/ampere

ampere/volt

Which of the following statements is false?

A body can have zero velocity and still be accelerated

A body can have a constant velocity and still have a varying speed

A body can have a constant speed and still have varying velocity

The direction of the velocity of a body can change when its acceleration is constant

A ball P is dropped vertically and another ball O is thrown horizontally with the same velocities from the same height and at the same time. If air resistance is neglected, then

ball P reaches the ground first

ball Q reaches the ground first

both reaches the ground at the same time

the respective masses of the two balls will decide the time

For a moving body at any instant of time

if the body is not moving, the acceleration is necessarily zero

if the body is slowing, the retardation is negative

if the body is slowing, the distance is negative

if displacement, velocity and acceleration at that instant are known, we can find the displacement at any given time in future

A body is moving in a circular path with a constant speed. It has

a constant velocity

a constant acceleration

an acceleration of constant magnitude

an acceleration which varies with time

A ball is thrown upwards and it returns to ground describing a parabolic path. Which of the following remains constant?

Kinetic energy of the ball ‘

Speed of the ball

Horizontal component of velocity

Vertical component of velocity

Newton’s second law gives the measure of

acceleration

force

momentum

angular momentum

A body is imparted motion from rest to move in a straight line. If it is then obstructed by an opposite force, then

the body may necessarily change direction

the body is sure to slow down

the body will necessarily continue to move in the same direction at the same speed

None of the above

A jet plane flies in the air because

the gravity does not act on bodies moving with high speeds

the thrust of the jet compensates for the force of gravity

the flow of air around the wings causes an upward force, which compensates for the force of gravity

the weight of air whose volume is equal to the volume of the plane is more than the weight of the plane

The momentum of a system is conserved.

Always

Never

In the absence of an external force on the system

None of the above

The force required to keep a body in uniform circular motion is

centripetal force

centrifugal force

resistance

None of the above

A person is sitting in a moving train and facing the engine. He tosses up a coin and coin falls behind him. It can be concluded that the train is

moving forward and gaining speed

moving forward and losing speed

moving forward with uniform speed

moving backward with uniform speed

A person sitting in an open car moving at constant velocity throws a ball vertically up into air. The ball falls

outside the car

in the car ahead of the person

in the car to the side of the person

exactly in the hand which threw it up

An athlete diving off high spring board can perform a variety of exercise in the air before entering the water body. Which one of the following parameter will remain constant during the fall?

The athlete’s linear momentum

The athlete’s angular momentum

The athlete’s kinetic energy

The athlete’s moment of inertia

Consider the following statements1. In railway track or road, the inner track/edge is comparatively less in height than the outer. 2. Washing machine is working on the principle of centrifugation. 3. A car takes a turn on level road. It may be thrown outwards because of the lack of centripetal force. Which of the statements given above is/are correct?

1, 2 and 3

1 and 3

2 and 3

Only 3

A person standing at the middle point of a wooden ladder which starts slipping between a vertical wall and the floor of a room, while continuing to remain in a-vertical plane. The path traced by a person standing at the middle point of the slipping ladder is

a straight line

an elliptical line

a circular path

a parabolic path

Which of the following statements are correct when a gymnast sitting on a rotating stool with his arms outstretched, suddenly lowers his hands? 1. The angular velocity decreases. 2. The angular velocity increases. 3. The moment of inertia decreases. 4. The moment of inertia increases. Select the answers using the codes given below.

1 and 3

1 and 4

2 and 3

2 and 4

A person is sitting in a car which is at rest. The reaction from the road at each of the four wheels of the car is R. When the car runs on a straight level road, how will the reaction at either of the front wheels vary?

It will be greater than R

It will be less than R

It will be equal to R

It shall depend on the materials of the road

A cricket player catches a fast coming ball by pulling his hands back because